<?php
/**
 * Created by PhpStorm.
 * User: ASUS
 * Date: 2016/9/23
 * Time: 10:08
 */
header('Content-type:text/html;chrset=utf-8');

$name='小明';
$score= 78;

if(is_int($score)  || is_float($score)){
    if($score>=90 && $score<=100){
        $str='A级';
    }elseif($score>=80 && $score<90){
        $str='B级';
    }elseif($score>=70 && $score<80){
        $str='C级';
    }elseif($score>=60 && $score<70){
        $str='D级';
    }elseif($score>=0 && $score<60){
        $str='E级';
    }else{
        $str='学生成绩范围必须在0~100！';
    }
}else{
    $str = '输入的学生成绩不是数值！';
}